Hard boiling them would make them easier to suck thought, wouldn't it? - more like a hard-boiled sweet. Raw egg would be easier to suck through a straw, providing you pierced the yoke. Sucking with the shell on would be quite difficult. An experiment is required - bring me half a dozen eggs, a stopwatch, a micrometer, a straw, nitrous oxide, some holy water and a grandma.

I can bring the plans for the one we built at uni - managed to shoot a spud from top floor of DC onto the windows of the Library..... until we decided to uprate the propellant..... then the weakest part was the plastic itself shall we say....